HI.
How can I load the Original bootloader inside the ATXMEGA for programming it with Flip?
When I use for first time the Atmel-Ice for programming, it probably cancelled the bootloader but sometimes I need to use Flip.

Almost every device that uses DFU has had a link to both AVR1916 application note and the accompanying AVR1916.zip code file in their list of "Documents" on atmel.com (in the recent transition to microchip it's true that some of the links have been "lost" so that has recently made it a little more difficult to find AVR1916.zip sometimes)

The only downside of the code is that you need IAR Embedded Workbench to build it. As most bootloaders build to less than 4K that should not be a problem as the "trial" version of IAR-EW AVR is free up to 4K. Above that it will cost you $3,000.